The structure of antigen, whether it is autologous or foreign, has profound effects on its perception by the immune system. Antigen valence, size, and epitope density are important determinants in its ability to induce important functional effects in B cells, including tolerance, activation (signal 1), proliferation and efficient antigen presentation to helper T-cells. Any such functional effects of antigen structure must reflect the quality or quantity of the signal transmitted through membrane immunoglobulin, in the B cell's receptor for antigen. The goal of this project is to identify how the B-cell is able to perceive and to interpret structural difference in antigens through its membrane Ig and associated transducer complex. To address these questions we have chosen to use immunoglobulin gene transgenic mice as a source of antigen-specific B-cells. Using a combination of heavy and light chain genes that encode antibody of defined specificity, mice can be designed which produce a large, homogeneous population of normal B-cells of predetermined specificity and affinity. This property of immunoglobulin gene transgenic mice facilitates a number of in vivo and in vitro studies by eliminating the extreme variability and heterogeneity of B-cell specificity of the normal immune system. B-cells from these transgenic mice will be challenged with synthetic polymers substituted with various amounts and densities of small haptens or peptides that are recognized by the antigen combining site of the transgenic B-cell's mIg. In producing these antigenic polymers we will take advantage of the most modern techniques in conjugate design, production, and quality control. We will systematically analyze conjugates of different architecture both for immunogenic and tolerogenic effects and the determine how these different functional effects correlate with early activation and signal transduction events. Ultimately, transgenic mice expressing dominant negative mutants of implicated signaling intermediaries, such as syk and CSK tyrosine kinases, will be used to define the role of specific effector enzymes in generation of biologic responses. The long-term goal is to apply this knowledge to the design of immunogenic and tolerogenic vaccines, and to develop pharmacologic agents for immunologic intervention in immunodeficiency and autoimmunity.